Tektronix 7704A User Manual

in t h e delayed
mo
d
e, current is ad d e d to t he Α
I NT EN SITY current d
uring t he Α sweep time to intensify α
portion of t h e trace
. T h is intensifie d portion is coinci d ent
with t he
Β -sweep time to provid e an indication of t h e
portion of t
he Α sweep t h at is d isplaye d in t h e delayed
mo d e .
T he Α Intensifie d current is sup p lied to pin 2 of
U 2587 from t
h e Α I NTE N SITY control t h roug h R 2586 .
Wit h t
h
is
configuration, t h e intensifie d current increases as
t
h e Α I N T EN SITY control setting is advance d to
provi de α
p roportional intensity increase in t
he intensifie d zone as t he
overall Α -sweep
intensity increases . T h erefore, t h e inten-
sifie d zone is
more rea d ily visible at h ig h intensity levels .
T h
e
intensifie d current is add e d to t h e
Α I N T EN SITY
cu rrent to produce an intensifie d zone on t
he Α sweep
under t h e following conditions : HI
Α
Gate
level at p in 14,
L O MF C hannel Switc
h Signal
at
p in 15, ΗΙ Β Gate level at
pin 4, HI Delay M ode
Control Out level at pin 5 an d t h e
base of Q2596, and
L OΑ H ol doff level at t h e emitter of
Q2596 .
T he Β I NT EN SITY control d
etermines t h e outp u t
current w hen t h e Β Gate level at
pin 4
an
d t h e MF Ch annel
Switc h Signal at pin 15
are bot h ΗΙ . T he current from t h e
Β
I N T EN SITY control (see d iagram 1) is connected to
t he
Ζ -Axis Logic stage t h roug h R2588 .
T h e current
level
esta
b lis hed by t he intensity controls
can be altere d by t
h e E xternal and Auxiliary Ζ -Axis
current
level at
pin
9 .
T he current at t h is p in can come from t
h e Ζ
AXIS
I NPU T connector on t h e rear p anel t
h
ro
u g h R
2092
or from
any
of
t h e plug-in com p artme n ts t
h
roug
h R 2090,
R2080,
R2012, or R2010 (see diagram 2) .
T h is current
eit h er increases or decreases ( d e p en d
ing on polarity) t h e
output c u rrent to modulate t
h e intensity of t h e d isplay .
Input from t h e Ζ AXIS I NPU
T connector allows t he trace
to
b e modulated by external signals .
T he auxiliary Ζ -Axis
in p u ts from t h e plug-in compartments allow
special pur p ose
plug-in u nits to modulate t
h e
display
intensity . Dio d es
C R 2585 and CR 2594 limit t
h e maximum voltage ch ange at
pi n 9 to about + and -0 .6
volt to p rotect t h e Ζ -Axis Logic
stage if an excessive voltage
is applie d to t h e Ζ AXIS
I NPU T connector .
F igure 2-9 Α s h ows α
logic d iagram of t h e Ζ -Axis Logic
stage .
N
otice t
h e current-driven inputs as in d icate d by t h
e
current-generator
symbols at t h e associated in p uts . An
input/out put table for t
he Ζ -Axis Logic stage is given in
F
ig . 2-9 Β .
H orizontal B inary
T h e MF ( M ain F rame) C hannel Switc
h Signal (Display
Β ) pro d uced by t h e
H orizontal Binary stage d etermi n es
w h ic h h orizontal
unit p rovi des t he sweep display on
t h e
C
R T . Wh
en t
h is level is ΗΙ , t he Β ΝΟ
R
ΙΖ unit is d
is p layed ;
w
h e n it is L O, t he Α H O R IZ unit is d isplayed .
T h e MF C hannel Switc h Signal (Dis p lay
Β )
is
used in t he
following stages wit
h
in t
he L
ogic
Circuit
:
H orizontal Logic
(for
Α
and
Β Swee p Lock out), Ζ -Axis L ogic (for blank ing),
and V ertical
Binary (to sync hronize vertical alternate
switc h ing wit
h h orizontal alternate switch ing) . In add ition,
t h is signal is
connecte d to t h e following circuits elsew h ere
in t
h e instrument : M ain Interface (to indicate w h ic h
h orizontal unit is to be d isplaye d
),
V ertical Interface (for
trace separation), an d H orizontal Interface (for h orizontal
c
h
annel selection)
.
N otice t h at t
he levels at p ins 3, 4, 7, an d 10 are
determine d by t
h e H O R IZO NTA L MOD
E
switc
h (see
d iagram 1) .
T h
is
switch determines w h ic h
h orizontal mo d e
h as been
selecte d by providing α Η Ι level to only
one of
four
out p ut
lines (t h e remaining lines are LO)
.
T h erefore,
at anyone
time, eit h er pin 3, pins 4 and 7 (notice t
h
at p
ins
4 and 7 are tie d
togeth er), or pin 10 can be HI and t
he
t
w o
unselecte d
lines from t h e H O R IZO
N TA L MOD E switch
remain
L O .
T h e H orizontal Binary stage operates as
follows for each
position of t
he H O R IZO N TA L M OD
E
switc
h (refer to F ig .
2-10 Β for
input/output conditions)
:
1 .
Α M OD E
Wh en t he H O R IZO N TA L M OD
E switch is set to Α , t h e
MF Ch annel Switc h Signal (Dis p lay
Β ) is L O to in d icate to
all
circuits t h at t he ΑΗΟ
R ΙΖ unit is to be d isplaye d .
2 . Β M OD
E
Selecting t
h e Β h orizontal mo de p
rovi d es α
HI
MF
Ch annel Switc h Signal (Dis p lay
Β )
to all
circuits .
3 . CH O
P M OD E
Circ
u
it Description
-7704A Service
In t
h e C HO P position of t h e H O
R IZO N TA L M OD E
switc
h ,
t
h e MF C h a n nel Switc
h
Signal
(Display Β ) switc h es
between t h e Η Ι and L O
levels
to p
roduce α display t h at
switch es b etween t he
Α H O R IZ an d Β H O R IZ units at α
200- kH z or 20- kH
z rate, as selecte d by S2510 .
T
h
e
repetition rate of t h
e
MF
Ch annel Switc h Signal (Display
Β )
in t h is mo d e is d
etermine d by t he H orizontal C h opped
Blan k ing pulse (see
C h op Counter d escription) .
E
ac
h time
t h e H orizontal C
h
op p
ed Blan k ing pulse at p in 1 d rops
L O,
the output at p
in 6 switch es to t he opp osite state
.
4 . A L
T
M OD
E
F or A L
T
h orizontal
operation, t he MF C h annel Switc
h
Signal (Display
Β ) switch es to t he opposite state eac
h
time
t he negative p ortion
of the Alternate P ulse is receive d from
the H orizontal
L ogic stage . Re p etition rate of t h
e MF
C hannel Switc
h Signal (Display Β ) in t h is mode is
one- h alf
t he re p
etition rate of t he Alternate P ulse ap p lie d to
pin
8 .
2- 1 5

Tektronix 7704A Specifications

General

Brand	Tektronix
Model	7704A
Category	Test Equipment
Language	English